The Mapster WP Maps plugin for WordPress is vulnerable to unauthorized modification of data that can lead to privilege escalation due to an insufficient capability check on the mapster_wp_maps_set_option_from_js() function in all versions up to, and including, 1.5.0. This makes it possible for authenticated attackers, with contributor-level access and above, to update arbitrary options on the WordPress site. This can be leveraged to update the default role for registration to administrator and enable user registration for attackers to gain administrative user access to a vulnerable site.